One-third of Children With COVID-19 Show No Symptoms

Approximately one-third of children with COVID-19 are asymptomatic, according to a study conducted by researchers at the University of Alberta.

Approximately one-third of children with coronavirus disease 2019 (COVID-19) are asymptomatic, according to a study conducted by researchers at the University of Alberta (UA). For this reason, children may be acting as silent carriers of the disease.

"The concern from a public health perspective is that there is probably a lot of COVID-19 circulating in the community that people don't even realize," said Finlay McAlister, MD, MSc, a professor of medicine in UA’s Faculty of Medicine & Dentistry, in a press release. "When we see reports of 1200 new cases per day in the province of Alberta, that's likely just the tip of the iceberg—there are likely many people who don't know they have the disease and are potentially spreading it."

The researchers analyzed the COVID-19 test results of 2463 children who were tested during the period of March to September of 2020. In total, 1987 children tested positive and 476 tested negative for COVID-19. Among the children with a positive test result, 714 children, or 35.9%, reported being asymptomatic.

"It speaks to the school safety programs," McAlister said in the press release. "We can do all the COVID-19 questionnaires we want, but if one-third of the kids are asymptomatic, the answer is going to be no to all the questions—yet they're still infected."

McAlister also noted that these results confirmed why a longer period of school closures in the province over the Christmas break was important.

"As far as we know, kids are less likely to spread disease than adults, but the risk is not zero," McAlister said in the press release. "Presumably asymptomatic spreaders are less contagious than the person sitting nearby who is sneezing all over you, but we don't know that for sure."

Additionally, the researchers found that 3 of the most common symptoms among children with COVID-19 infection—cough, runny nose, and sore throat—were not predictive of a positive COVID-19 test result, as more children with a negative result presented with these symptoms than children with a positive result.

"Of course, kids are at risk of contracting many different viruses, so the COVID-specific symptoms are actually more things like loss of taste and smell, headache, fever, and nausea and vomiting, not runny nose, a cough and sore throat," McAlister said.

McAlister noted that these results are similar among adults as well. In another study his team is conducting and plans to publish in the near future, the researchers demonstrate that although 84% of adults with sore throats and runny noses tested positive for COVID-19, these symptoms are not predictive of a positive test result.

"Sore throat and runny nose means you've got some kind of upper respiratory tract infection, but fever, headache, and loss of taste or smell are the big ones for indicating that one may have COVID-19 rather than another viral upper respiratory tract infection," McAlister said in the press release, additionally noting that nausea and vomiting were not as prominent in adults as they are in children.

McAlister explained that for these reasons, anyone with any symptoms should stay at home and get tested. However, even those who feel well should continue to be safe by wearing protective masks, frequently washing their hands, keeping a safe distance from others, and avoiding indoor gatherings.

"Some people with COVID-19 feel well and don't realize they have it, so they socialize with friends and unintentionally spread the virus, and I think that's the big issue," McAlister said in the press release.


More than one-third of children with COVID-19 show no symptoms: study. Alberta, CA: University of Alberta Faculty of Medicine & Dentistry; November 30, 2020. Accessed January 11, 2021.